Pickling metals



PdtentJFbfii", 1531 UNITED STATES VANDERVIJER VOORHEES, OF WRITING,

txamme PATENT OFFICE INDIANA, ASSIGNOB TO STANDARD OIL COMPANY, OF WHITING, INDIANA, A CORPORATION OF INDIANA PICKLING METALS Io Drawing. Continuation of application Serial No. 121,279, filed July 8, 1926. This application filed January 18, 1928.

This invention relates to the acid pickling of metals, and particularly to the reduction of hydrogen evolution and loss of metals therein. 5 According to the present invention hydrogen evolution and excessive attack of the metal are substantially reduced or prevented in the cleaning of metals, particularly ferrous metals, by pickling in an acid bath consisting wholly or in part of acid derived iromacid sludgeffom'the'sifliiific acid treatment of a ti'oleumpilwhich-has been subjected to cracking temperatures. It is preferred to employ acid derivedfrom sludge resulting from the tmatment with sulfuric acid of oils cracked under pressure at temeratures which are usually in excess of 700 Serial No. 247,746.

to about to H SO and further a tgamed This treatment efl'ectively drives dors. The resulting aci 1s a clear, brownish red liquid which may be diluted directly to a concentration suitable for the picklin operation ornnafi he adm1xed with other sicid and diluted. 0 tarry mata iggn sludges derived irom distilmdilution and its odor late .procncts siid h as cracked gasoline and kero e are referred. As a specific examp e 1 may e stated that good results are obtained with acid recovered from sludge resulting from the treatment of pressure distillate, produced, for example, by the Burton process at temperatures of 720-7 60 F. and

is greatly improved.- The deodorized strong acid is relatively inactive towards ferrous metals and may suitably be transported in steel tank cars to the places where it is to be diluted and used in pickling.

It must be understood that the invention is not limited to the use of an acid derived 7n pressures above 4 atmospheres, with sulfuric from a sludge frompressure distillate, since agid of about 66 Baum although other acid strengths may 53 employed if desired. While the restraining effect with regard to metal attack is possessed by the pressure distillate sludge, to a high degree, a preliminary treatment is necessary in order to avoid several objections which arise in actual practice. For example, if such sludge is diluted to the extent necessary to produce a pickling bath of normal acid content there would be a tend ency for asphaltic matters to precipitate upon the metal under treatment, thereby preventing efi'ective pickling and causing imerfections in the finished metal when subected to tinning or other subsequent operations. Another objection is that the sludge possesses a nauseating odor when raised to pickling temperature. Both these disadvantages can be substantially completely overgood results may be obtained with acid from sludges derived from other distillates and residues from the various known cracking processes.

According to the invention, the pickling bath may be of any suitable concentration and may be used at any suitable temperature. Ordinarily the initial concentration used is between 5 and 10% of sulfuric acid although higher concentration may used? Corrosion ss (mgml. per square inch) Proportion of acids 100% pure acid 75% pure arid 25% sludge acid 85% pure acid 15% sludge acid 95% pure acid 5% sludge acid This application is a continuation of my prior application Serial No. 121,279, filed July 8, 1926.

I claim:

1. The method of acid pickling metals which comprises subjecting the metal to the action of a pickling bath containing acid and incorporating in said bath organic substances recovered from sludge derived from a cracked petroleum distillate soluble in dilute sulfur1c acid, said or anic substances being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

2. The method of acid pickling metals which comprises subjecting the metal to the action of an acid pickling bath and incorporating in said bath organic substances derived from the sludge from acid treatment of a pressure cracked distillate and soluble in dilute sulfuric acid, said organic substances being free from sludge substances soluble in strong sulfuric acid, and not soluble in dilute sulfuric acid.

3. The method of acid pickling metals which comprises subjecting the metal to the action of an acid pickling bath and incorporating in said bath a material recovered from petroleum acid sludge containing organic substances therefrom soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

4. The method of acid pickling metals which comprises subjecting the metal to the action of an acid pickling bath and incorporating in said bath a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances thereof as are soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

5. The method of acid pickling metals which comprises subjectin the metal to the action of an acid pickling ath and incorporating therein a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid and free from sludge substances soluble in strong sulfuric acid and not soluble in'dilute sulfuric acid, the acid of such material constituting from 5 to 25% of the total acid in the bath.

6. The method of preparing a bath for pickling metals which comprises diluting acid sludge derived from a cracked petroleum oil with water, heating to cause separation of asphaltic matter and incorporating the acid and accompanying organic substances soluble therein in a metal pickling bath.

7. The method of producing a metal pickling bath which consists in diluting sludge from the sulfuric acid treatment of cracked distillate with water, heating to cause separation of asphaltic material and expel odors, removing the asphaltic material and einbodv- 'ing the acid and accompanying organic substances soluble therein in a suitable stren h.

8. A solution for pickling iron or steel articles, comprising water and a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

9. A solution for pickling iron or steel articles, comprising commercial sulfuric acid, water and a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfurc acid and not soluble in dilute sulfuric ac1 10. A solution for pickling iron or steel articles containing as an ingredient a material recovered from petroleum acid sludge consisting of sulfuric acid and such organlc substances as are soluble in dilute sulfuric acid, and free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

11. A solution for pickling iron or steel articles containing as ingredients commercial sulfuric acid and a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid, and free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

12. A solution for pickling iron and steel articles containing as ingredients commercial sulfuric acid and a material recovered from petroleum acid sludge consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid and free from sludge substancessoluble in strong sulfuric acid and not soluble in dilute sulfuric acid,

pickling bath of 252. COMPOSITIONS,

the proportion of said material being such that the acid content thereof constitutes not less than 5% of the total acid of the bath.

13. A solution for pickling1 iron and steel articles comprising water an a material recovered from acid sludge from the treatment of cracked petroleum distillate and consisting of sulfuric acid and such organic substances as are soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuricjcid and insoluble in dilute sulfuric acid.

14. A solution for pickling iron or steel articles comprising commercial sulfuric acid. water and a material recovered from acid sludge from the treatment of cracked petroleum distillate and comprisin organic substances therefrom soluble in ilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

15. A solution for pickling iron or steel articles comprising sulfuric acid, water and a material recovered from etroleum acid sludge and containing suc organic substances thereof as are soluble in dilute sulfuric acid, said material being free from sludge substances soluble in strong sulfuric acid and not soluble in dilute sulfuric acid.

In testimony whereof I have hereunto set my hand this 4th day of January, 1928.

VANDERVEER VOORHEES. 

